OK I've solved the problem.
I added a class:
Then filled it after the InitializeComponent():
ObjectDataProvider oDP = (ObjectDataProvider)this.FindResource("oDropList");
if (oDP !=
DropList l = (DropList)oDP.Data;
I added this to the XAML:
And changed my bindings to:
I am now able to dynamically refresh the drop down list. By the way, the sample classes here were laid out to be similar to Linq relational data query results, so this should work with that type of data. Hopefully this solution helps someone else someday.